The frilled shark, often described as a “living fossil,” is a fascinating deep-sea dweller. With its eel-like body and six pairs of frilly gill slits, it looks unusual and almost prehistoric. Despite its formidable appearance, the frilled shark poses virtually no threat to humans. This is due to its deep-sea habitat and specialized physical adaptations.
A Creature of the Deep
Human encounters with the frilled shark are exceedingly rare, primarily because its natural habitat is in the deep ocean, far removed from human activities. These sharks typically reside near continental shelves and slopes, at depths ranging from 400 to 4,200 feet (120 to 1,280 meters), though they have been observed as deep as 5,150 feet (1,570 meters). While they have a widespread, patchy global distribution across the Atlantic, Pacific, and Indian Oceans, their preference for such profound depths means they are infrequently sighted.
This deep-water preference significantly limits human interaction. Most recreational diving and swimming occur in shallow coastal waters, making accidental encounters highly improbable. The few instances where frilled sharks are seen near the surface are usually when caught as bycatch in deep-sea fishing, or when they ascend to shallower, cooler waters. These infrequent sightings highlight their status as a rarely observed species.
Built for Its World, Not Our Waters
The frilled shark’s physical characteristics and predatory behaviors are specifically adapted for its deep-sea environment and the prey available there. Its long, slender, eel-like body, which can reach up to 6.6 feet (2 meters) in length, is well-suited for serpentine movements and ambush predation in the deep sea. Rather than actively chasing prey, it is thought to strike like a snake, lunging forward to capture unsuspecting organisms.
Its mouth, positioned at the front of its head, contains multiple rows of unique, needle-sharp teeth, totaling around 300 in about 25 rows. Each tooth has three sharp points that curve inward, designed for gripping soft-bodied, slippery prey like squid, octopuses, and small fish, which constitute its primary diet. These teeth are not structured for tearing into large, muscular prey, such as mammals. The frilled shark’s hunting strategy, relying on stealth and a quick lunge to swallow prey whole, does not involve aggressive behaviors or jaw strength that would pose a danger to humans.